PS2 (Ext)-6
Students demonstrate an understanding of physical, chemical, and nuclear changes by... 6aa-using chemical equations and information about molar masses to predict quantitatively the masses of reactants and products in chemical reactions.
National Standards:
Context of Lesson:
During this lesson students will be introduced to the concept of a mole and how it relates to chemical compounds. Students will be presented with the types of questions asked that prompted Amedeo Avogadro to determine a number that could be used to define the number of units contained in a particular sample of a compound. They will be faced with the challenge of understanding that if a single representative particle of a compound is very small (the size of an atom or group of atoms) that even a small sample of the compound will hold a very large number representative particles.
Opportunities to Learn:
Depth of Knowledge
Can you look at each of your tasks and summarize what DOKs are used?
Prerequisite Knowledge
Prior to instruction students should be familiar with:
The Periodic Table
Chemical Compounds and their construction (ionic bonding/covalent bonding)
The content of Chapter 7, section 7.1 (previous class's reading assignment)
Diatomic Molecules
Good.
Plans for Differentiating Instruction
Some students will experience difficulty with the factor-label method (linear conversions) and should be given additional simple conversion problems for practice before they begin using the mole. Stress the importance of labels. If you know this is going to be a problem, will you have a tutorial sheet that leads them through some extra problems step by step? What about the students that catch on quickly?
Accommodations and modifications
This lesson can be modified in the number of example problems necessary for students to understand and be able to apply the concepts being presented.
Environmental factors
The desks are set up in rows and there is a smartboard that can be used located in the front of the room. If applicable - desks can be grouped in 2s for work on practice problems if the students are having trouble on their own.
Materials
Example Problems
Photograph of a mole
Periodic table
Milk jug
Egg carton
Objectives:
After instruction students will be able to:
Describe how Avagadro's number is related to a mole of any substance.
Calculate the mass of a mole of any substance.
Make connections to the Periodic Table.
Instruction:
Opening: This will be presented in Powerpoint form (2-3 slides)
Atoms are extremely small, so small that we need a special microscope to see them. Often in Chemistry we have the need to count how many atoms are in a particular substance, yet if atoms are so small how are we able to do this? Answer: We use a measurement called the Mole.
Have a picture of an actual mole (animal) up on the smart board as students are entering the classroom. This will eventually be replaced by a picture of Amedeo Avogadro whose work led to the experimentally determined mole, 6.02x10^23. This will be followed by a brief description of what they see up on the board. Questions will be asked:
Who can tell me what this is (referring to the picture of the animal)? Answer: A mole
Who can tell me who this is (referring to Avogadro)? Answer: Amedeo Avogadro
Who can tell me what scientific concept Avogadro is responsible for? Answer: The mole - 6.02x10^23
Engagement:
Begin by showing the students the empty milk jug and egg carton. Ask questions:
How much milk fits into this bottle? Answer: 1 gallon
How many eggs fit into this carton? Answers: 12 or one dozen Why not ask: If this container is full, how many eggs would I have? How do you know? You could do the same with a ream of paper.
Who can tell me what a representative particle is? Answer: the species present in a substance - usually atoms, molecules, or formula units (ions).
One mole of any substance (atoms, molecular compounds, or ionic compounds) are always said to contain 6.02x10^23 representative particles.
Examples of a representative particles: One representative particle of Carbon Dioxide, a molecular compound, (CO2) is made up of one carbon atom and two oxygen atoms, Helium is made up of Helium atoms, Silver is made up of Silver atoms, diatomic molecules such as H2 will contain two Hydrogen atoms in one representative particle (O2, N2, F2, Cl2, are all examples of diatomics). In short, the representative particle of all elements and all molecular compounds is referred to as the molecule. If we are referring to ionic compounds, such as NaCl (table salt), we use the term formula units. i.e. calcium chloride is composed of Ca+ and Cl- ions, thus, it is an ionic compound and will be measured in formula units.
Now make the connection: We can count how many eggs are in one dozen, however it is almost impossible, and very impractical, to try and count how many representative particles of a compound (i.e. H2O) are in say 1mL of solution. So instead we call that number of particles a mole (mol) of that compound. Good.
So if we are trying to determine how many molecules are in one mole of a molecular compound such as CO2 we simply take one mole of CO2 and use the conversion factor 6.02x10^23 molecules/1 mol of CO2 to determine how many molecules we will have (show the linear conversion equation)
If we are trying to determine how many atoms are in one mole of a molecular compound such as CO2 we must perform the conversion we just did, however we must add another step. We must count how many atoms make up CO2 (there are 3 - 1 Carbon atom and 2 Oxygen atoms). We can then use the conversion factor 3 atoms/1 molecule of CO2 to determine how many atoms there are in one mole of CO2. Why not ask them to tell you how to determine the number of atoms in a mole of CO2 before you explain it?
Example: Say there are 5 sticks of gum in each package of gum. One package of gum is like one molecule and the sticks of gum are like the atoms that make up the molecule. Let's use a number similar to a mole say one dozen. If we wanted to know how many sticks of gum are in one dozen packs of gum we would perform the following conversion (show the conversion):
1 dozen packs of gum x 12 packs of gum/1 dozen x 5 sticks of gum/1 pack of gum Are you going to explain the idea of a "conversion factor" at this point? The Mass of a Mole of an Element
Let's first define the term gram atomic mass(gam). The gam is simply the atomic mass of an element expressed in grams.
Where do we find the atomic mass? Answer: the periodic table
For example: Carbon has an atomic mass of ......? Answer: 12 amu (atomic mass units)
So, we can say that one atom of Carbon has a (gam) of .....? Answer: 12.0g That's a pretty heavy atom.
What is the gam of Oxygen? Answer: 16.0g
So, if we were to compare 12.0g of C and 16.0g of O how many atoms do we have of each? Answer: Both are equivalent to 1 atom This is not clear. It sounds like you are saying that 1 atom of carbon has a mass of 12 grams.
We can now also say that one mole of C contains 12.0g of C. Similarly, we can say that one mole of any element is equal to the element's gam.
The Mass of a Mole of a Compound
How do we now determine the mass of one mole of a compound? Answer: Use the chemical formula to determine the type and number of elements that make up the compound and then add them up.
First, we must take a look at the chemical formula. For example: SO3, which is called? Answer: Sulfur trioxide
Second, we must determine the type and number of atoms that make up the compound. For example: SO3 is made up of 1 Sulfur atom and 3 Oxygen atoms (draw this out to give students a visual).
Third, we must determine the masses (from the periodic table) of all of the atoms that make up the compound and add them together. For example: 1 S atom = 32.1 amu and 3 O atoms = 3(16.0 amu) for a total of 80.1 amu
Last, we must change our units from amu to g so that the mass is expressed in grams. So, we can say that the mass of one mole of SO3 = 80.1g. This is referred to as the gram molecular mass (gmm).
Calculating the gram molecular mass values is an important skill that you will use very often in chemistry. Why? Can you give them an example of when this would be useful?
Give the students this sample problem: The molecular formula for hydrogen peroxide is H2O2, what is the gmm? Answer: 34.0g H2O2 (have solution written out)
Break from lecturing/examples and have students try some practice problems:
Find the gmm of each compound:
C2H6
PCl3
C3H2OH
N2O5
What is the mass of 1.00mol of each substance.
chlorine
nitrogen dioxide
carbon tetrabromide
silicon dioxide
Have students work on these problems and then report their solutions by putting the problems up on the board and explaining their work.
Ionic Compounds
The representative particle for an ionic compound is what? Answer: a formula unit
So, the mass of one mole of an ionic compound such as calcium iodide (CaI2) is referred to as the gram formula mass (gfm).
A gfm is calculated the same way that a gmm is. For example: one mole of CaI2 can be determined by adding the masses 1 Ca atom and 2 I atoms, 40.1g Ca + 2(126.9g I) = 293.9g CaI2. So there are 293.9g of CaI2 in 1 gfm or 1 mole of CaI2.
If there are any problems with conceptualizing this give students additional practice with example problem 7-5 on pages 180-181 in their textbooks.
Closure:
Leave ample time (10 minutes or so) for questions/review of concepts presented. Assign reading: Section 7.2 - pp. 182-186. Students should be advised that they should pay close attention to the following concepts in the reading:
Molar mass and how it relates to gam, gmm, and gfm
The molar volume of a gas
The Mole Road Map - How do we convert to and from volume, mass, and number of representative particles when given either volume, mass, or number of representative particles?
If students appear to be having trouble grasping the material assign section review 7.1: 11-15 for homework instead of reading section 7.2. Why not ask them to represent this knowledge in a chart or table? It is hard to get students to read if there is not an associated task.
Assessment:
Students will be formatively assessed periodically throughout the class in their ability to understand the material being presented. This will be accomplished by posing questions (found throughout the lesson) to test student's knowledge. If homework is assigned it will be collected and gone over during the next class period.
Nice lesson. Well written plan. When you get a chance, you should upload your powerpoint file and you should have solutions to all the example problems that you will use.
Lesson Plan
Lesson Title: The Mole as a Measurement of Matter
State Standards: GLEs/GSEs
PS2 (Ext)-6Students demonstrate an understanding of physical, chemical, and nuclear changes by...
6aa-using chemical equations and information about molar masses to predict quantitatively the masses of reactants and products in chemical reactions.
National Standards:
Context of Lesson:
During this lesson students will be introduced to the concept of a mole and how it relates to chemical compounds. Students will be presented with the types of questions asked that prompted Amedeo Avogadro to determine a number that could be used to define the number of units contained in a particular sample of a compound. They will be faced with the challenge of understanding that if a single representative particle of a compound is very small (the size of an atom or group of atoms) that even a small sample of the compound will hold a very large number representative particles.Opportunities to Learn:
Depth of Knowledge
Can you look at each of your tasks and summarize what DOKs are used?
Prerequisite Knowledge
Prior to instruction students should be familiar with:Good.
Plans for Differentiating Instruction
Some students will experience difficulty with the factor-label method (linear conversions) and should be given additional simple conversion problems for practice before they begin using the mole. Stress the importance of labels. If you know this is going to be a problem, will you have a tutorial sheet that leads them through some extra problems step by step? What about the students that catch on quickly?Accommodations and modifications
This lesson can be modified in the number of example problems necessary for students to understand and be able to apply the concepts being presented.Environmental factors
The desks are set up in rows and there is a smartboard that can be used located in the front of the room. If applicable - desks can be grouped in 2s for work on practice problems if the students are having trouble on their own.Materials
Objectives:
After instruction students will be able to:Instruction:
Opening: This will be presented in Powerpoint form (2-3 slides)
Atoms are extremely small, so small that we need a special microscope to see them. Often in Chemistry we have the need to count how many atoms are in a particular substance, yet if atoms are so small how are we able to do this? Answer: We use a measurement called the Mole.Have a picture of an actual mole (animal) up on the smart board as students are entering the classroom. This will eventually be replaced by a picture of Amedeo Avogadro whose work led to the experimentally determined mole, 6.02x10^23. This will be followed by a brief description of what they see up on the board. Questions will be asked:
Engagement:
Begin by showing the students the empty milk jug and egg carton. Ask questions:- How much milk fits into this bottle? Answer: 1 gallon
- How many eggs fit into this carton? Answers: 12 or one dozen Why not ask: If this container is full, how many eggs would I have? How do you know? You could do the same with a ream of paper.
- Who can tell me what a representative particle is? Answer: the species present in a substance - usually atoms, molecules, or formula units (ions).
- One mole of any substance (atoms, molecular compounds, or ionic compounds) are always said to contain 6.02x10^23 representative particles.
Examples of a representative particles: One representative particle of Carbon Dioxide, a molecular compound, (CO2) is made up of one carbon atom and two oxygen atoms, Helium is made up of Helium atoms, Silver is made up of Silver atoms, diatomic molecules such as H2 will contain two Hydrogen atoms in one representative particle (O2, N2, F2, Cl2, are all examples of diatomics). In short, the representative particle of all elements and all molecular compounds is referred to as the molecule. If we are referring to ionic compounds, such as NaCl (table salt), we use the term formula units. i.e. calcium chloride is composed of Ca+ and Cl- ions, thus, it is an ionic compound and will be measured in formula units.Now make the connection: We can count how many eggs are in one dozen, however it is almost impossible, and very impractical, to try and count how many representative particles of a compound (i.e. H2O) are in say 1mL of solution. So instead we call that number of particles a mole (mol) of that compound. Good.
- So if we are trying to determine how many molecules are in one mole of a molecular compound such as CO2 we simply take one mole of CO2 and use the conversion factor 6.02x10^23 molecules/1 mol of CO2 to determine how many molecules we will have (show the linear conversion equation)
- If we are trying to determine how many atoms are in one mole of a molecular compound such as CO2 we must perform the conversion we just did, however we must add another step. We must count how many atoms make up CO2 (there are 3 - 1 Carbon atom and 2 Oxygen atoms). We can then use the conversion factor 3 atoms/1 molecule of CO2 to determine how many atoms there are in one mole of CO2. Why not ask them to tell you how to determine the number of atoms in a mole of CO2 before you explain it?
Example: Say there are 5 sticks of gum in each package of gum. One package of gum is like one molecule and the sticks of gum are like the atoms that make up the molecule. Let's use a number similar to a mole say one dozen. If we wanted to know how many sticks of gum are in one dozen packs of gum we would perform the following conversion (show the conversion):1 dozen packs of gum x 12 packs of gum/1 dozen x 5 sticks of gum/1 pack of gum Are you going to explain the idea of a "conversion factor" at this point?
The Mass of a Mole of an Element
Let's first define the term gram atomic mass (gam). The gam is simply the atomic mass of an element expressed in grams.
- Where do we find the atomic mass? Answer: the periodic table
- For example: Carbon has an atomic mass of ......? Answer: 12 amu (atomic mass units)
- So, we can say that one atom of Carbon has a (gam) of .....? Answer: 12.0g That's a pretty heavy atom.
- What is the gam of Oxygen? Answer: 16.0g
- So, if we were to compare 12.0g of C and 16.0g of O how many atoms do we have of each? Answer: Both are equivalent to 1 atom This is not clear. It sounds like you are saying that 1 atom of carbon has a mass of 12 grams.
We can now also say that one mole of C contains 12.0g of C. Similarly, we can say that one mole of any element is equal to the element's gam.The Mass of a Mole of a Compound
How do we now determine the mass of one mole of a compound? Answer: Use the chemical formula to determine the type and number of elements that make up the compound and then add them up.
- First, we must take a look at the chemical formula. For example: SO3, which is called? Answer: Sulfur trioxide
- Second, we must determine the type and number of atoms that make up the compound. For example: SO3 is made up of 1 Sulfur atom and 3 Oxygen atoms (draw this out to give students a visual).
- Third, we must determine the masses (from the periodic table) of all of the atoms that make up the compound and add them together. For example: 1 S atom = 32.1 amu and 3 O atoms = 3(16.0 amu) for a total of 80.1 amu
- Last, we must change our units from amu to g so that the mass is expressed in grams. So, we can say that the mass of one mole of SO3 = 80.1g. This is referred to as the gram molecular mass (gmm).
Calculating the gram molecular mass values is an important skill that you will use very often in chemistry. Why? Can you give them an example of when this would be useful?Give the students this sample problem: The molecular formula for hydrogen peroxide is H2O2, what is the gmm? Answer: 34.0g H2O2 (have solution written out)
Break from lecturing/examples and have students try some practice problems:
Find the gmm of each compound:
- C2H6
- PCl3
- C3H2OH
- N2O5
What is the mass of 1.00mol of each substance.- chlorine
- nitrogen dioxide
- carbon tetrabromide
- silicon dioxide
Have students work on these problems and then report their solutions by putting the problems up on the board and explaining their work.Ionic Compounds
The representative particle for an ionic compound is what? Answer: a formula unit
- So, the mass of one mole of an ionic compound such as calcium iodide (CaI2) is referred to as the gram formula mass (gfm).
- A gfm is calculated the same way that a gmm is. For example: one mole of CaI2 can be determined by adding the masses 1 Ca atom and 2 I atoms, 40.1g Ca + 2(126.9g I) = 293.9g CaI2. So there are 293.9g of CaI2 in 1 gfm or 1 mole of CaI2.
If there are any problems with conceptualizing this give students additional practice with example problem 7-5 on pages 180-181 in their textbooks.Closure:
Leave ample time (10 minutes or so) for questions/review of concepts presented. Assign reading: Section 7.2 - pp. 182-186. Students should be advised that they should pay close attention to the following concepts in the reading:If students appear to be having trouble grasping the material assign section review 7.1: 11-15 for homework instead of reading section 7.2. Why not ask them to represent this knowledge in a chart or table? It is hard to get students to read if there is not an associated task.
Assessment:
Students will be formatively assessed periodically throughout the class in their ability to understand the material being presented. This will be accomplished by posing questions (found throughout the lesson) to test student's knowledge. If homework is assigned it will be collected and gone over during the next class period.Nice lesson. Well written plan. When you get a chance, you should upload your powerpoint file and you should have solutions to all the example problems that you will use.
Reflections
(only done after lesson is enacted)Student Work Sample 1 – Approaching Proficiency:
Student Work Sample 2 – Proficient:
Student Work Sample 3 – Exceeds Proficiency: